Unexpected behavior with microTask

[Charles Lindsay]

I'm submitting a bug report

• Library Version:
  1.1.0

Please tell us about your environment:

• Operating System:
  Windows [10]

• Node Version:
  5.1.0

• NPM Version:
  3.10.8

• JSPM OR Webpack AND Version
  CLI

• Browser:
  Chrome 53

• Language:
  ESNext

Current behavior:
My microTask fires, but apparently still too early in the lifecycle and I'm not getting my desired results, however, if I wrap my code into a setTimeout(()=>{},1) then I get my desired results.

This code works...

    bind() {
        if (this.appState.scrollPosition)
            this.taskQueue.queueMicroTask(() => {
                setTimeout(() => {
                    $('body').scrollTop(this.appState.scrollPosition);
                },1);
            });
    }

    canDeactivate() {
        this.appState.scrollPosition = $("body").scrollTop();
        return true;
    }

Expected/desired behavior:
This code should work, but does not...

    bind() {
        if (this.appState.scrollPosition)
            this.taskQueue.queueMicroTask(() => {
                $('body').scrollTop(this.appState.scrollPosition);
            });
    }

    canDeactivate() {
        this.appState.scrollPosition = $("body").scrollTop();
        return true;
    }

• What is the expected behavior?

I am expecting this code to work, without the need for the setTimeout()

• What is the motivation / use case for changing the behavior?

I thought this used to work without the setTimeout... however currently I need the setTimeout to get my desired results.

[stsje]

Is there a reason for why you're not scrolling in the attached life cycle hook? The DOM element is not yet attached when bind is invoked. In the attached hook you probably don't even need to queue a task.

You could also try with queueTask instead of a micro task.

[Charles Lindsay]

@stsje Beautiful... thank-you :)